Method and device for operating a drive device, and drive device

Abstract

A method for operating a drive device of a motor vehicle, having an internal combustion engine and at least one switchable mechanism. The mechanism can be switched to change an operating state influencing a fuel consumption and switching causes an increased fuel consumption. It is proposed that a torque and a rotational speed of the internal combustion engine are predicted depending on a current operating situation, that a dwell time of the mechanism in a switching state is predicted depending on the torque and the rotational speed, and that the mechanism for changing the operating state is actuated depending on the dwell time.

The invention claimed is: 
     
       1. A method for operating a drive device of a motor vehicle, having an internal combustion engine and at least one switchable mechanism, the at least one switchable mechanism comprising at least one of a shift transmission having several transmission stages and a valve stroke adjustment device of a variable valve train of the internal combustion engine,
 wherein the mechanism can be switched to change an operating state influencing a fuel consumption, and a process of switching the at least one switchable mechanism causes an increased fuel consumption, 
 wherein a torque and a rotational speed of the internal combustion engine are predicted depending on a current operating situation, and a predicted dwell time of the mechanism in a switching state is determined depending on the torque and the rotational speed, 
 wherein the current operating situation includes: 
 a driver type identification based on a gas pedal position, a brake pedal position, and a steering wheel angle; 
 a current travel route based on a navigation system determining one or more of hills, slopes, stops or speed-reducing restricted zones; and 
 traffic information along the current travel route from a traffic control system, 
 wherein a minimum dwell time is determined based on a probable fuel consumption which is predicted based on the current operating situation, and compared to the increased fuel consumption caused by the process of switching the at least one switchable mechanism, and if the predicted dwell time is longer than the minimum dwell time, the mechanism for changing the operating state is actuated. 
 
     
     
       2. The method as claimed in  claim 1 , wherein an ignition angle and/or a fuel supply of the internal combustion engine is/are varied upon switching in such a way that a driving torque of the drive device remains the same or almost the same during the switching. 
     
     
       3. The method as claimed in  claim 1 , wherein the mechanism is actuated depending on a dwell time-dependent fuel consumption. 
     
     
       4. The method as claimed in  claim 1 , wherein the probable fuel consumption is determined depending on an operating range of the internal combustion engine. 
     
     
       5. The method as claimed in  claim 1 , wherein the probable fuel consumption is determined depending on the determined rotational speed and the determined torque. 
     
     
       6. A device for operating a drive device of a motor vehicle, comprising:
 an internal combustion engine and at least one switchable mechanism, wherein the mechanism can be switched to change an operating state influencing a fuel consumption and a process of switching the at least one switchable mechanism causes an increased fuel consumption, 
 wherein a specially designed control unit, which, when used as intended, carries out the method as claimed in  claim 1 . 
 
     
     
       7. A drive device for a motor vehicle, comprising:
 an internal combustion engine having at least one switchable mechanism and a device as claimed in  claim 6 , 
 wherein the at least one switchable mechanism can be switched to change an operating state influencing a fuel consumption and a process of switching the at least one switchable mechanism causes an increased fuel consumption.